Hardware is a Dell T420 Dual Quad Core Processors with 24 GB of RAM and Mirrored Hard Drives. 3 Virtual Machines all running 2012 Standard with all patches. 1 VM is AD Controller, 1 VM is an app server for a lightweight management app, and 1 VM is a RDS server for 10 users.
There are 2 NIC cards on this server with are Broadcom. Currently we have 1 NIC dedicated to the Microsoft Virtual Switch and the other dedicated to the Host. We have a gigabit Firewall / 8 Port swtich in place and all appeared to be working just fine until we started testing the RDS sessions.
RDS from any network device was extremely choppy and slow even though it was on the same Gigabit switch. Tried swapping around the adapters and same issue. Tried different cables and switches with the same problem. Finally tried connect to the RDS server from the Host system and again slow.
Switch the Host to share the same Adapter as the Virtual Switch and everything was smooth as silk from the Host in the RDS session, however other devices still choppy.
Tested file copies to / from the servers and received expected performance. This only seems to be a problem when using Remote Desktop to the RDS server. Tried all kinds of changes to TCP Offloading as well as toggling just about every option possible on the NIC cards of both the host and VM as well as the remote systems. No improvements.
Running a ping from the client to the RDS server produced high ping times whenever anything was occurring in the RDS session.
So as a last resort we deleted the current NIC's in the VM configurations and replaced them with Legacy adapters and RDS suddenly ran smooth both locally and remotely. Ping times stated at < 1 ms while in our RDS session. Switched back to the Integration Services option (which is recommended) and everything is slow again.
I would say that switching to the legacy cards is the fix except file transfer rates are now 4x slower than they were to begin with. I am now at a loss to figure out what to do here as we need to install this system in a few days and I am out of ideas.
What should we do next to try to isolate or fix the problem?